How do I show 10 degree of precision after decimal for float data type in C

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C++

C

I am using Turbo C on Windows 7. When I declare a float and such as float f1 = 6.6666666
and try to show it with printf("%0.7f", f1); it shows shows some at random value after four correct digits of precision after decimal. It works fine for double data type. Why is that? Please help! Here is my program:-

#include<stdio.h>

void main(void)
{
float f1=6.6666666;
double d1 = 6.6666666;

printf("%0.7f \t %0.7f", f1,d1);
}

It works fine for double but it shows random value after 4 digits of precision after decimal for float. Please help!